Tuning of dielectric and impedance properties of PVDF by incorporation of Mg doped PZT

Abstract

Ferroelectric polymer nanocomposites of poly(vinylidene fluoride) (PVDF) and Mg doped PZT (PMZT) have been prepared by solvent casting method. The existence of β, γ and δ polar phases and α nonpolar phase of PVDF have been observed from the X-ray diffraction (XRD) and FTIR analysis. Both rhombohedral as well as tetragonal crystal phases of PZT at morphotropic phase boundary (MPB) is also observed. The characteristic peaks of PVDF in the FTIR spectra are unaffected with the incorporation of PMZT. Dielectric properties were studied as a function of frequency and temperature. The microstructure of PVDF–PMZT composite has been studied by employing SEM technique. Maximum dielectric constant of 32 with minimum dielectric loss of 0.0053 were obtained at 100 kHz for 6 mol% PMZT composite. The ac conductivity follows the Jonscher power law which exhibits the least value of interaction between mobile ions and lattice. Both grain and grain boundary contributions have been considered to explain the impedance behavior of the sample. The optimum loading percentage of PMZT in PVDF matrix is found to be 6 mol%. The structural results obtained from XRD and FTIR are well correlated with the physical parameters obtained from impedance measurement.